make sure micronaut-servlet works on Payara server

[kbachl]

Follow up to:
#7 and payara/Payara#4661

Payara server will always make a validation run of any war even CDI scanning is disabled. The io.micronaut.http.client.DefaultHttpClient.stop() with @PreDestroy while not beeing in any CDI will then lead to an error.
Since master of micronaut 2 changed that code part already it is necessary to add a test to make sure the micronaut-servlet runs on payara and therefore it works as expected.

Also the Documentation of micronaut-servlet should be enhanced making clear that it is important to no include Java EE dependencies like Servlet API, CDI API, etc into the war by making them scope provided. This might even be enforced by a check on compile-time by micronaut-servlet